Vulnerability in Sigstore Sigstore-Java

CVE-2026-48791

sigstore-java is a sigstore java client for interacting with sigstore infrastructure. Version 2.0.0 erroneously removed verification of the integrated (Rekor entry) time) against the Fulcio certificate. Version 2.1.0 re-added this verification with enhancements that adhere to the Sigstore verification spec. The old sigstore-conformance test for this check was built incorrectly. This vulnerability impacts only users verifying bundles with `dev.sigstore:sigstore-java:2.0.0`. Older versions are not affected; it is fixed in `dev.sigstore:sigstore-java:2.1.0` A malicious actor may exploit this if they were able to access a users system and exfiltrate the temporary private key used during signing and then reuse an old fulcio certificate later without requiring direct access to the user's credentials. Users may protect themselves by re-verifying their artifacts using the newest sigstore-java or another current sigstore client. Transparency logs may also be audited for unauthorized signatures for a suspected reused identity.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 2.0 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.001 (0.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 0th percentile — 0.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-48791: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: -0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-48791?
CVE-2026-48791 is a low-severity vulnerability in Sigstore Sigstore-Java, classified under Improper Verification of Cryptographic Signature. CVSS score: 2.0/10. Published 2026-08-13.
How severe is CVE-2026-48791?
Low severity. CVSS v3 base score is 2.0 out of 10.